Yesterday's opening arguments set the tone for how each side will frame the case. The LA Timessummarizes:

In his opening argument, [Theodore Olson] called marriage "one of the most vital personal rights" and a "basic civil right." Withholding it from gays and lesbians "doesn't make sense," he said.

U.S. District Judge Vaughn R. Walker asked if the state should simply get out of the business of issuing marriage licenses.

"That may solve the problem," Olson said, but it "would never happen."

Walker also asked Olson if voters are entitled to pass laws stemming from "moral disapproval," such as prohibitions on alcohol.

Olson replied that U.S. history is filled with moral condemnation of people based on their race, gender and ethnicity. Proposition 8, passed by 52.3% of California voters in 2008, perpetuates discrimination "for no good reason," Olson said.

Charles J. Cooper, who is representing the Proposition 8 campaign and has argued many cases before the Supreme Court, told Walker that a limitation of marriage to opposite-sex couples has "prevailed in virtually every society since early history."

Walker noted that many states once barred interracial marriage. Cooper replied that those laws were based on a notion of "white supremacy," and not on a long-standing tradition.

Cooper said the evidence would show that opposite-sex marriage is good for children, and that the "procreative purpose of marriage" would be "diluted or weakened" if same-sex couples were permitted to marry.

Asked what evidence exists to show that same-sex marriage would "radically alter the institution of marriage," Cooper replied that data from the Netherlands will show that it leads to a decline in marriage rates. He said it also would lead to more children being raised outside of marriage and higher divorce rates.

Andrew Sullivan posted excerpts of Olson's opening statement (the full remarks can be found here), focusing on how Olson dismantled many of the opposition's arguments. Here's the most concise part of Olson's arguments, explaining how Proposition 8 created a strange legal snare with little justification outside of prejudice:

The State of California has offered no justification for its decision to eliminate the fundamental right to marry for a segment of its citizens. And its chief legal officer, the Attorney General, admits that none exists. And the evidence will show that each of the rationalizations for Proposition 8 invented by its Proponents is wholly without merit.

"Procreation" cannot be a justification inasmuch as Proposition 8 permits marriage by persons who are unable or have no intention of producing children. Indeed, the institution of civil marriage in this country has never been tied to the procreative capacity of those seeking to marry.

Proposition 8 has no rational relation to the parenting of children because same-sex couples and opposite sex couples are equally permitted to have and raise children in California. The evidence in this case will demonstrate that gay and lesbian individuals are every bit as capable of being loving, caring and effective parents as heterosexuals. The quality of a parent is not measured by gender but the content of the heart.

And, as for protecting "traditional marriage," our opponents "don't know" how permitting gay and lesbian couples to marry would harm the marriages of opposite-sex couples. Needless to say, guesswork and speculation is not an adequate justification for discrimination. In fact, the evidence will demonstrate affirmatively that permitting loving, deeply committed, couples like the plaintiffs to marry has no impact whatsoever upon the marital relationships of others.

When voters in California were urged to enact Proposition 8, they were encouraged to believe that unless Proposition 8 were enacted, anti-gay religious institutions would be closed, gay activists would overwhelm the will of the heterosexual majority, and that children would be taught that it was "acceptable" for gay men and lesbians to marry. Parents were urged to "protect our children" from that presumably pernicious viewpoint.

At the end of the day, whatever the motives of its Proponents, Proposition 8 enacted an utterly irrational regime to govern entitlement to the fundamental right to marry, consisting now of at least four separate and distinct classes of citizens: (1) heterosexuals, including convicted criminals, substance abusers and sex offenders, who are permitted to marry; (2) 18,000 same-sex couples married between June and November of 2008, who are allowed to remain married but may not remarry if they divorce or are widowed; (3) thousands of same-sex couples who were married in certain other states prior to November of 2008, whose marriages are now valid and recognized in California; and, finally (4) all other same-sex couples in California who, like the Plaintiffs, are prohibited from marrying by Proposition 8.

There is no rational justification for this unique pattern of discrimination. Proposition 8, and the irrational pattern of California's regulation of marriage which it promulgates, advances no legitimate state interest. All it does is label gay and lesbian persons as different, inferior, unequal, and disfavored. And it brands their relationships as not the same, and less-approved than those enjoyed by opposite sex couples. It stigmatizes gays and lesbians, classifies them as outcasts, and causes needless pain, isolation and humiliation.

It is unconstitutional.

Much of yesterday's testimony focused on the personal stories behind the fight for marriage equality. Kristin M. Perry, (who brought the case to court) talked about falling in love with her partner, Sandra B. Stier. Perry was asked what it means to be a lesbian, and if she could conceive of changing her sexual orientation.

Ms. Perry, for instance, said that she had tried dating boys when she was growing up in rural Bakersfield, Calif., if only for a chance to "have a date for the prom," but that she had always known she was a lesbian.

Asked by Mr. Olson if she could change her sexual feelings, Ms. Perry paused, then replied: "I'm 45 years old. I don't think so.

The statements to watch today will come from Nancy Cott, who Olson and Boies hope will shoot holes through the idea of "traditional" marriage:

Nancy Cott, a U.S. history professor at Harvard and the author of a book on marriage as a public institution, is scheduled to take the witness stand for a second day. Cott, a witness appearing on behalf of two gay couples who are suing to overturn Proposition 8, on Monday disputed assertions made by the measure's sponsors during the 2008 campaign that cultures around the world always have recognized marriage only as a union of a man and a woman.

"To think of marriage as universal, the same around the globe, simply is not accurate," Cott said, explaining that America's founders knew that group marriages were common in other societies and among some Native American tribes. "The Bible is a document with characters that are practicing polygamy, which is the case with ancient civilizations."

After Cott is cross-examined by lawyers for Proposition 8's backers, who are defending the voter-approved initiative in court, Yale history professor George Chauncey is expected to testify about anti-gay bias. Chauncey also was an expert witness in a landmark gay rights case that resulted in the U.S. Supreme Court invalidating a 1992 Colorado law that sought to prevent cities from extending civil rights protections to gays.

Chauncey's testimony will also be vital as the supporters of Proposition 8 will need to prove that there is a reason outside of bigotry to deny same sex couples the right to marry. Since the Supreme Court has already ruled that laws motivated by bigotry are unconstitutional, the onus is on Cooper to find a justification that would avoid allegations of bigotry.

I personally can't wait to watch Cooper try to roll that boulder uphill.